Any of the 'open source' tools will work as intended. The closed source tools require a license to work properly.
From the LAStools README.txt file that is included in the download, open source tools (i.e., tools that do not add noise) include the following:
open source tools:
- laszip.exe compresses the LAS files in a completely lossless manner
- lasinfo.exe prints out a quick overview of the contents of a LAS file
- lasindex.exe creates a spatial index LAX file for fast spatial queries
- las2las.exe extracts last returns, clips, subsamples, translates, etc ...
- lasmerge.exe merges several LAS or LAZ files into a single LAS or LAZ file
- txt2las.exe converts LIDAR data from ASCII text to binary LAS format
- las2txt.exe turns LAS into human-readable and easy-to-parse ASCII
- lasprecision.exe analyses the actual precision of the LIDAR points
Closed source tools that require a license include:
closed source
tools:
lastool.exe is an old GUI for multiple LAStools (now each tool has its own GUI)
lasground.exe extracts the bare-earth by classifying all ground points
lasground_new.exe an improved version of lasground.exe for complex terrains
lasoverlap.exe checks overlap & vertical/horizontal alignment of flight lines
lascontrol.exe quality checks elevations for a list of control points
lasclassify.exe finds buildings and the vegetation above the ground
lascolor.exe colors the LAS points based on ortho imagery in TIF format
lasgrid.exe grids onto min/max/avg/std elevation, intensity, or counter rasters
lascanopy.exe computes many raster and plot metrics for forestry applications
lasboundary.exe extracts a boundary polygon that encloses the points
lasheight.exe computes for each point its height above the ground
lastrack.exe classifies LiDAR point based on distance from a trajectory
lasplanes.exe finds planar patches in terrestrial, mobile, (airborne?) scans
lasclip.exe clips points against building footprints / swath boundaries
lastile.exe tiles huge amounts of LAS points into square tiles
lassplit.exe splits points of LAS file(s) into flightlines or other criteria
lassort.exe sorts points by gps_time, point_source, or into spatial proximity
lasduplicate.exe removes duplicate points (with identical x and y, z optional)
lasthin.exe thins lowest / highest / random LAS points via a grid
las2tin.exe triangulates the points of a LAS file into a TIN
las2dem.exe rasters (via a TIN) into elevation/slope/intensity/rgb DEMs
las2iso.exe extracts, optionally simplified, elevation contours
lasview.exe visualizes a LAS file with a simple OpenGL viewer
las2shp.exe turns binary LAS into ESRI's Shapefile format
shp2las.exe turns an ESRI's Shapefile into binary LAS